Angioplasty is a well known technique that is commonly used in the treatment of vasculature diseases. An integral part of an angioplasty procedure is the insertion of an inflatable balloon on a catheter into the vasculature of a patient to position the balloon in a vessel at the site of a stenosis. The balloon is then inflated to dilate the stenosis.
A recent innovation in angioplasty procedures involves ablation of a stenosis by an inflated balloon with an incising component mounted on the outer surface of the balloon. Typically the so-called “cutting balloon” will have a plurality of atherotomes (blades) mounted on its outer surface. Once the “cutting balloon” is inflated inside the vessel, the blades create small incisions in the lesion which facilitate dilation of the stenosis and reduce barotrauma. Such a “cutting balloon” is disclosed and claimed in U.S. Pat. No. 5,797,935 which issued to Barath for an invention entitled “Balloon Activated Force Concentrators for Incising Stenotic Segments” and which is assigned to the same assignee as the present invention. While the “cutting balloon” is one example of an interventional medical device that has been developed for performing certain in situ procedures, it is possible for other external components to be mounted on a catheter balloon for therapeutic or diagnostics purposes.
Regardless of the specific incising component that may be mounted on the balloon, a recurring problem is damage that may happen to the balloon during insertion of the catheter or after the balloon inflation and deflation sequence. Prior to insertion, the balloon is typically folded into a so-called “taco shape” or “spiral fold” configuration to reduce its overall profile. Typically, the balloon will come from the manufacturer in this folded configuration. An incising component mounted on the surface of the balloon may, however, prevent the balloon from being folded into its most compact configuration, and may damage the balloon. In addition, damage may occur as the balloon is being maneuvered through the vasculature of a patient. Despite careful manipulation of the catheter through the vasculature system, balloon material may be pushed against the incising surface, damaging the balloon and causing an unwanted rupture.
Yet another opportunity for damage occurs after the balloon has been used for its intended purpose, and is subsequently deflated and withdrawn from the vessel. After deflation, the balloon again collapses inwardly toward its center, for example into a modified “X” configuration. When blades or other incising components are mounted on the balloon, to be located between the legs of the “X”, the balloon is particularly vulnerable to damage. Specifically, damage can occur in this configuration if the balloon material is pushed against the incising component during passage through tortuous anatomy or during a twisting of the catheter.
In addition to the problems discussed above, balloon material may have a tendency to fold back on itself, along the axis of the balloon, as the distal end of the balloon contacts the vessel wall or obstructions in the vessel. Importantly, a balloon with an incising component mounted on the outer surface will be more rigid in the area of the incising component. As such, the balloon will tend to fold back, or “kink”, in less rigid areas, potentially causing balloon material to fold over and come into contact with the incising component.
In light of the above, it is an object of the present invention to provide a reinforced balloon to protect the areas of the balloon that are likely to be damaged by an incising component. Another object of the present invention is to provide a reinforced balloon that helps to minimize collateral damage to the tissue of a patient. Still another object of the present invention is to provide a balloon that helps to minimize balloon damage resulting from the balloon folding back on itself. Yet another object of the present invention is to provide a reinforced balloon with components mounted on its surface that is easy to use, relatively simple to manufacture, and comparatively cost effective.